<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>buybook</title>
</head>

<body>
    <div id="app">
        <div>
            <p>请选择你要购买的书籍</p>
            <ul>
                <li v-for="(book, index) in arr" :key="index">
                    {{ book.name }}
                    <button @click="addBook(index)">买书</button>
                </li>
            </ul>
            <table border="1" width="500" cellspacing="0">
                <tr>
                    <th>序号</th>
                    <th>书名</th>
                    <th>单价</th>
                    <th>数量</th>
                    <th>合计</th>
                </tr>
                <tr v-for="(book, index) in arr" :key="index">
                    <td>{{ index + 1 }}</td>
                    <td>{{ book.name }}</td>
                    <td>{{ book.price }}</td>
                    <td>{{ book.count }}</td>
                    <td>{{ book.price * book.count }}</td>
                </tr>
            </table>
            <p>总价格为: {{ total }} 元</p>
        </div>
    </div>
    <script src="./vue.js"></script>
    <script>
        const app = new Vue({
            el: '#app',
            data: {
                arr: [
                    { name: "水浒传", price: 107, count: 0 },
                    { name: "西游记", price: 192, count: 0 },
                    { name: "三国演义", price: 219, count: 0 },
                    { name: "红楼梦", price: 178, count: 0 },
                ],
                total: 0
            },
            methods: {
                addBook(index) {
                    this.arr[index].count += 1;
                    this.calculateTotal();
                },
                calculateTotal() {
                    this.total = this.arr.reduce((sum, book) => sum + (book.price * book.count), 0);
                }
            },
            watch: {
                arr: {
                    deep: true,
                    handler() {
                        this.calculateTotal();
                    }
                }
            }
        });
    </script>
</body>

</html>